This application relates to rotors, and more particularly to rotor airfoils of integrally bladed rotors.
Gas turbine engines are known and typically include a fan delivering air into a bypass duct for propulsion. The fan also delivers air into a compressor where air is compressed and delivered into a combustor. The air is mixed with fuel and ignited. Products of this combustion pass downstream over turbine rotors driving them to rotate. The turbine rotors, in turn, rotate compressor rotors and the fan rotor. The fan rotor and the turbine rotors include blades having airfoils that extend radially outward from a hub. Traditionally, rotor blades have been removable from the hub.
Integrally bladed rotors (IBRs) are used in some gas turbine engine applications, and are provided by a unitary structure that includes a hub from which a plurality of non-removable circumferentially arranged rotor blades radially extend. IBRs eliminate individual blade attachments. IBRs have been used for both fan and compressor applications.
IBR rotor blades may be subjected to high vibratory stress during gas turbine engine operation. Because IBR rotor blades are integrally formed with the rotor hub, that high vibratory stress may also extend to the rotor hub from which the blades extend.